Influence of bio-regulators on the seed germination and seedling growth of onion cultivars

application of bio-regulators improves the productivity of cash crops. current experiment evaluates the effects of different doses of a bio-regulator on the seed quality of three onion cultivars ('baia periforme', 'bola precoce' and 'híbrida superex'). six doses of bio-regulator at 0, 2.5, 5.0, 10.0, 20.0 and 30.0 ml kg-1 were applied and results were compared to those of three controls. the experimental design was entirely randomized under the factorial arrangement 3 x 6 + 3, with four replications. data were subjected to analysis of variance (p < 0.05), and all seed treatments were compared with controls by dunnett's test. the analysis of regression described the effects of the increasing doses of bio-regulator on germination and vigor responses which were evaluated by the first count of the germination test, the percentage of germination and the length of the roots and shoots of the normal seedlings. the application of the bio-regulator did not improve the percentage of seed germination and no positive response of the seedlings was reported from the cultivars 'baia periforme' and 'bola precoce'. however, seedling vigor of 'híbrida superex' was positively affected by the application of the bio-regulator.